WASHINGTON — A German man filed a lawsuit Tuesday claiming he was held captive and tortured by U.S. government agents after being mistakenly identified as an associate of the Sept. 11 hijackers. Later Tuesday, the U.S. State Department and diplomatic sources in Germany confirmed for NBC News that the man, Khaled al-Masri, can now travel to the United States — an about-face of U.S. authorities from days earlier.

Al-Masri, who is being represented by the American Civil Liberties Union, said he was arrested while attempting to enter Macedonia for a holiday trip and flown to Afghanistan. During five months in captivity he was subjected to “torture and other cruel, inhuman or degrading treatment,” said a lawsuit he filed in U.S. District Court in suburban Alexandria, Va.

As a result of an NBC News report about al-Masri being turned away in Atlanta, U.S. officials traveling with Secretary of State Condoleezza Rice have assured German officials that he is no longer on a watch list.

At an ACLU news conference in Washington, al-Masri’s lawyer revealed that U.S. authorities on Saturday night refused to let al-Masri into the country.

Merkel meets with RiceGerman Chancellor Angela Merkel said the U.S. has acknowledged making a mistake in the man’s arrest. “I’m happy to say we have discussed the case, which the government of the United States has of course accepted as a mistake,” Merkel said after meeting with Rice.

The suit names as the main defendant former CIA Director George Tenet. In addition to torture, he claims his due process rights were violated and that he was subjected to “prolonged, arbitrary detention.” He is seeking damages of at least $75,000.

“I am asking the American government to admit its mistakes and to apologize for my treatment,” said al-Masri in a written statement. “Throughout my time in the prison, I asked to be brought before a court but was refused. Now I am hoping that an American court will say very clearly that what happened to me was illegal and cannot be done to others.”

Through a translator he described how he was kidnapped from Macedonia and allegedly tortured by his CIA interrogators.

The CIA “rendition” program, in which terrorism suspects are captured and taken to foreign countries for interrogation, has been heavily criticized by human rights groups.

The ACLU claims it has standing to sue in a U.S. district court based on constitutional restrictions on U.S. officials, even when the events involved occur on foreign soil. They also say al-Masri has standing under a 2004 Supreme Court ruling regarding the right of aliens to sue.

Asked what proof they had that Tenet knew the CIA was holding the wrong man, ACLU officials cited an
NBC report which aired last spring
and recent follow-up reports in the Washington Post.

Amnesty International details claimsThe scope of the program has not been disclosed by the CIA. However, Amnesty International claimed Monday that six planes used by the CIA for renditions have made some 800 flights in or out of European airspace, including 50 landings at Shannon International Airport in Ireland.

Al-Masri, 42, was born in Kuwait to Lebanese parents and moved to Germany in 1985. The married father of five said that on New Year’s Eve 2003 he boarded a bus in his hometown of Neu-Ulm for a holiday in Macedonia. At the border he was stopped by Macedonian authorities and his passport was confiscated.

He said he was arrested by local authorities for 23 days and then handed over to what he believes was a team of CIA operatives. He then was flown to Afghanistan where he was subjected to abuse during four months in captivity.

In late May 2004 he was flown to Albania and then put on a plane back to Germany.